change two LGTMs requirement to one

Signed-off-by: Liang Chenye <[email protected]>

Author: liangchenye

MAINTAINERS_GUIDE.md

@@ -64,7 +64,7 @@ All decisions are pull requests, and the relevant maintainers make
 decisions by accepting or refusing the pull request. Review and acceptance
 by anyone is denoted by adding a comment in the pull request: `LGTM`.
 However, only currently listed `MAINTAINERS` are counted towards the required
-two LGTMs.
+one LGTM.
 
 Overall the maintainer system works because of mutual respect across the
 maintainers of the project.  The maintainers trust one another to make decisions